Process of making graphophone-blanks



UNITED STATES PATENT OFFICE.

THOMAS II. MACDONALD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THEAMERICAN GRAPIIOPIIONE COMPANY, OF VEST VIRGINIA.

PROCESS OF MAKING GRAPHOPHONE-BLANKS.

SPECIFICATION forming part of LettersPatent No. 626,709, dated June 13,1899.

Application filed August 23, 1898. Serial No. 689,351. (No Specimens.)

To all whom, it may concern:

Be it known that I,THOMAS H. MAoDoNALD, of Bridgeport, Connecticut, haveinvented a new and useful Improvement in Graphophone-Tablets andProcesses of Manufacturing the Same, which improvement is fully setforth in the following specification.

My invention relates to the art of manufacturing blanks or tablets uponwhich soundrecords may be out or engraved, and more particularly to theprocess of treating the composition of matter of which the tablet iscomposed to the end that the same may be perfectly amorphous, free fromall fibrous or other organic impurities, and without tendency tocrystallization.

In forming a sound-record the method described in United States PatentNo. 341,214 is now commonly employed, which method consists in cuttingor engraving an undulatory groove in the surface of a suitable tablet bymeans of a cutting-style attached to a vibratory diaphragm upon whichthe sounds to be recorded are allowed to impinge. The force of thesound-waves is very weak, and it is essential to the accomplishment ofthe best results that the surface of the tablet should be such as toenable the style to cut a smooth undulatory line whose undulations shallcorrespond exactly to those of the recorded sound-waves. If there is anycrystalline formation or any tendency thereto in the surface of thematerial composing the tablet, the shaving removed by the style isliable to follow the line of cleavage of the crystal, thus ofieringvariable resistance to the action of the style and producing a groovewhose irregularities do not correspond exactly to the undulations of therecorded sound-waves. It is also very important that the composition ofmatter composing the tablet should be free from all fibrous or otherorganic matter, as such otters uneven resistance to the cutting actionof the style, causing it to form a rough and inaccurate record. In somecases the style rides over the fiber and makes no record at all, causingwhat is known as blind spots. In other cases the style fails to cut thefiber, but pulls it out bodily, leaving a hole or depression where thereshould have been a smooth out. Again, the style, instead of cutting thefiber or removing it bodily, tears through it, leaving rough jagged endswhich when the rubbing style of a reproducer rubs over them give a roughharsh quality to the reproduced sound. Moreover, the organic matter isliable to ferment and mildew, greatly lessening the value of the blankand destroying the record out therein. In my Patent No. 606,725, datedJuly 5, 1898, I have described and claimed a process for making blapktablets whereby a superior tablet may be produced which is to a largeextent lacking in the objectionable features above described and uponwhich records of a high order of merit may be produced. I have found,however, that there is often a tendency to form crystals upon thesurface of blanks made by such process, which tendency is due to thepresence in the blank of the water of crystallization. I have alsolearned that such tablets sometimes contain fibrous or other organicimpurities, such as fine dust particles, which are at all times floatingin the air and which the most vigilant care could not entirely exclude.

The object of the present invention is to produce a blank tablet whichshall be without any tendency to crystallization and in which allfibrous matter shall be destroyed; and to this end the inventionconsists in subjecting the composition of matter which is to constitutethe tablet to a degree of heat suflicient to entirely drive 01f allwater of crystallization and entirely destroy all fibrous and otherorganic impurities in the composition of matter.

Heretofore in the treatment of the composition of matter of which thetablets were to be formed heat has been resorted to for the purpose ofeliminating the water; but great care has been taken not to exceed atemperature of about 330 Fahrenheit for fear of charring the compositionand thereby rendering it unfit for use as a tablet material. This temperature was not sufiicient to entirely eliminate the water ofcrystallization and would not destroy fibrous and other organicmatter. Ihave discovered, however, that the composition of matter may beadvantageously subjected to a heat of from 450 to 475 Fahrenheit, andthat by so doing the water of crystallization may be entirely eliminatedand the fibrous and other organic impurities eliminated ordisintegrated.

For the purpose of illustrating my invention and the best method knownto me for putting the same into practice I will describe one compositionof matter and the process of forming and treating the same preparatoryto molding it into tablet form.

Formula: Stearic acid, free from oleic acid and glycerin, four hundredand eight pounds; alu minic hydrate, seven pounds; caustic=soda lye,eighty-five pounds. To this is added for the purpose of temperingparaffin, ozocerite, or similar material, seventy-two pounds. Thecaustic soda is incorporated in water until a lye of 37.5 Baum isobtained, and this is heated to its boiling-point, about 242 Fahrenheit.The aluminic hydrate is added and is quickly taken up by the lye. Thestearic acid is melted and raised to about the same temperature, and thecompound'of lye and aluminium slowly added thereto. It will unitereadily therewith. It is preferred to employ about the temperatureindicated, as thereby the formation of the composition proceedsgradually and without violent ebullition. The temperature of the moltenmass is then raised to a point somewhere between 450 and 475 Fahrenheit.When the desired temperature has been reached, I allow the same to fallabout 100 and then pour the mass into the molds in the usual manner. Thefall of the temperature may be conveniently secured by putting out thefire and allowing the mass to stand a few moments.

It is not, of course, essential that all the ingredients constitutingthe compound material should first be incorporated in the mixture beforeheating the same to the high temperature required to drive off the waterof crystallization and destroy all organic matter, as the ingredientsmay, if it is found advantageous, be heated separately to the highdegree necessary, or partial combinations may be formed, these heatedtoa high degree, and then the partial combinations united to form thefinished compound. I prefer, however,

to first incorporate and thoroughly unite all I claim as new, and desireto secure by Letters Patent, is'- 1. In the process of making asound-record ing material, the improvement consisting in partiallysaponifying stearic acid, and then heating the mass to a temperature ofabout 460 Fahrenheit, substantially as described.

2. In the process of making a sound-recording material, the improvementconsisting in mixing stearic acid with caustic-soda lye, and thenheating the mass to about 460 Fahrenheit.

3. The improvement in the process of making sound-recording materialwhich consists in heating such material to about 460 Fahrenheit, thencooling the same down to about 360 Fahrenheit, and then molding thematerial into the desired shape, substantially as described.

4. The process of making a sound-recording material consisting indissolving aluminium in soda-lye, adding the solution to stearic acid,and raising the temperature of the mass to about 460 Fahrenheit,substantially as described.

5. The process of making a sound-recording material, said processconsisting in addin g to stearic acid soda-lye with which a metal hasbeen united, the lye being in such quantity as to'produce partialsaponification, and heating the mixture to about t60 Fahrenheit,substantially as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

THOMAS H. MACDONALD.

Witnesses:

HENRY A. I-IUBBELL, E. W. SULHIE.

